VOL. XII, NO.8 ENGINEERING AND SCIENCE MONTHLY MAY 1949

Comparison of pictures taken by the IOO-inch (left) and 200-inch telescopes shows the kind of minute detail obtainable by the Hale telescope (arrow, right) which is of utmost significance to astronomers.

.. UIETLY and without fanfare, on the night of "t January 26th, 1949, at 10:06 p.m. P.S.T., Dr. Edwin Hubble pulled the slide of the plate holder start­ing the exposure on plate number P.H..-I. The P stands for Palomar, the H for Hale, and the 1 means that this was the first astronomical photograph taken on the first observing schedule of the 200-inch Hale telescope at Palomar Mountain. To date 62 plates have been taken with the 200-inch telescope.

To the layman these first photographs will probably look just like thousands of other astronomical photo­graphs, taken with other large telescopes. To the astronomer, however, these first Palomar plates are tremendously exciting. Even though they were taken under from poor to average conditions of "seeing," they clearly indicate that the 200-inch Hale telescope i.s capable of doing the work for which it was designed.

These first observations have already pushed back the horizons of our observable universe from 500 million to 1,000 million light years. Some of the plates show detail and resolution equal to the finest plates thus far taken with the lOa-inch telescope on Mt. Wilson. The light-gathering power of the 200-inch mirror as­sures stellar and nebular spectrograms on a greater scale and with finer detail than ever heretofore obtain­able. Due to the novel design of the Hale telescope a large area about the North Pole, not withiI} the range

PE takes its first pictures

by EDISON ROGE

P.H.-I, first picture taken with the 200-in. telescope is not much-astronomically speak. ing--since it was only made to tryout the telescope. Taken by Dr. Hubble, it shows Hubble's V ariable Nebula.

MAY 1949-3

Spiral nebula, left, was photographed by the lOO-in_ telescope; same nebula, right, by the 200-in. telescope.

Unexciting?

Blow-up of 200-inch plate reveals nebula's nucleus.

4-MAY 1949

" Unfortunately," says Dr . Hubble, "the most exciting pictures astronomically (the ones where the most distant objects have been photographed) become the least spectacular ... on the printed page". But these pictures of a nebula 5,000,000 light years away' seem to contradict Dr. Hubble's modest statement.

of the lOa-inch telescope, now becomes observable with a very large telescope for the first time.

These first plates from Palomar were taken as a practical test of the great telescope. When first installed, the 200-inch mirror was given a thorough optical test in place by Dr. Ira Bowen. The outer 20 inches of the mirror was found to be turned up a few millionths of an inch. To correct this minute irregularity it has been decided to polish this outer rim down to as nearly the correct figure as possible. This work, which will take about six months, will bring the 200-inch Hale telescope to its highest possible working efficiency before the regular observing program is resumed.

Advancement in scientific research is not always ac­complished by merely building larger and more power­ful equipment. New types of instruments often result in great advances too. The 48-inch Schmidt telescope at Palomar admirably illustrates this point. Although the 4,8-inch Schmidt has not been much publicized, it will be of outstanding importance in the astronomical re­search program at Palomar.

The Schmidt type of telescope is unique in that it may photograph with a relatively short exposure a very

No other astronomical instrument can obtain as vast a region of the sky as the 48-inch Schmidt camera which scouts the skies for the 200-inch, and creates a good

large area of the sky in exquisite detail. This makes it extremely valuable as a "mapping" telescope, with great possibilities for discovering new astronomical ob­jects. The 200-inch Hale telescope, on the contrary, has an extremely narrow angle of view, but the 200-inch reflecting mirror gives a very great light gathering power and the large diameter provides a very high de­gree of resolution. These unique characteristics of the

deal of astronomical excitement on its own. This typical plate (the original is approximately 14" x 14") was taken in the center of the central line of our Milky Way.

200-inch telescope are well adapted to examining in detail-both by direct photography and by spectro­graphic photography-astronomical objects that may I.e discovered with the Schmidt telescope.

The future, indeed, holds great promise for the Palo­mar astronomers who may use this team of great tele­scopes to expand our basic knowledge of the universe about us. CONTINUED ON PAGE 6

MAY 1949-5

Enlargement of section of Schmidt plate shows details of Rosette Nebula-a cloud of dust and gas illuminated by hot blue stars in the cloud. '

Further enlargement (six times) shows dark markings in Rosette Nebula in sharp detail. Nebula is in Minoceros in the Milky Way.

The 48-inch Schmidt finds a window in the Milky Way

Enlargement of a section of the Schmidt plate shown on page 5 reveals an opening or "window" (fuzzy ob­ject in center of picture above) in the gas and dust clouds of the Milky Way. Through it, astronomers saw

6-MAY 1949

a nebula never before found in thl~s region. It would have been sheer luck if this nebula had been found by an instrument like the 200-inch telescope, which has a high degree of resolution but an extremely narrow field.